The present invention relates to a compressor including an oil-mist separator.
JP-A-7-243391 discloses a cyclone type oil separator in which an oil is separated from a gas flowing out of a compressor by utilizing a centrifugal force applied to the gas.
An object of the present invention is to provide a compressor including an oil-mist separator, in which a mist of lubrication oil is separated effectively from a gas after being compressed, in a simple and cheap structure.
In a compressor for compressing a mixture gas including a mist of lubrication oil and a gas to be taken out of the compressor with a pressurized condition, comprising, a pair of compressing members movable with respect to each other so that the mixture gas is compressed therebetween, an electric motor for driving at least one of the compressing members to generate a relative movement between the compressing members for compressing the mixture gas, and an oil-mist separator for separating the mist of lubrication oil from the mixture gas to collect the lubrication oil, according to the present invention, the oil-mist separator includes an inner surface forming a chamber for receiving the mixture gas, an inlet passage for directing a flow axis of the mixture gas when the mixture gas reaches the chamber, and a discharge passage includes a discharge port opening in the chamber to discharge the gas from the chamber through the discharge port.
Since the discharge port of the discharge passage opens in the chamber, that is, the mixture gas surrounds circumferentially the discharge port to swirl around the discharge port, a concentration of the mist of lubrication oil at the discharge port is kept small by a centrifugal force applied to the mist of lubrication oil.
It is preferable for generating effectively the centrifugal force suitable for separating the mist of lubrication oil from the mixture gas that the chamber is cylindrical, and/or the chamber and the discharge passage or discharge port are coaxial.
If a tubular member whose inner surface forms the discharge passage projects in the chamber to be surrounded circumferentially by the mixture gas, that is, the mixture gas surrounding the discharge passage extends longitudinally along the discharge passage formed in the tubular member in the chamber and contacts the tubular member with a large contact area therebetween, the swirl flow of the mixture gas is formed around the discharge passage of tubular member to separate the mist of lubrication oil away from the discharge passage or port, and a temperature of the tubular member is kept high although the discharge passage communicates with the outside of the compressor or oil-mist separator, to restrain a vapor of the lubrication oil from being liquefied on the tubular member so that the mist of lubrication oil is restrained from being introduced into the discharge passage. It is preferable for restraining the mist of lubrication oil from proceeding in the discharge passage toward the outside of the compressor or oil-mist separator that the tubular member projects vertically downward in the chamber, that the discharge port is prevented from facing to the inlet passage, and/or that the discharge port opens vertically downward.
It is preferable for effectively separating the mist of lubrication oil from the mixture gas by the centrifugal force that the inlet passages extends in such a manner that the flow axis of the mixture gas is directed by the inlet passage to an annular part of the inner surface so that the swirl flow of the mixture gas is effectively generated along the annular part of the inner surface, and/or that the inlet passages extends in such a manner that the flow axis of the mixture gas directed by the inlet passage is prevented from being perpendicular to an imaginary tangential plane of a point of the inner surface on the flow axis so that the mixture gas directed by the inlet passage is restrained from being divided at the point of the inner surface to at least two mixture gas components whose flow directions are opposite to each other.
It is preferable for restraining the mist of lubrication oil separated from the mixture oil at the inner surface from being introduced into the discharge port or passage that a baffle is arranged between the discharge port and the inner surface to bend a flow direction of the mixture gas toward the discharge port so that the mist of lubrication oil is collected by the baffle. It is preferable for increasing a mist collection efficiency of the baffle that the baffle includes a sheet having through-holes through which the mixture gas is allowed to flow toward the discharge port, or that the baffle includes a pair of the sheets, and each of the sheets has the through-holes so that a flow direction of the mixture gas toward the discharge port is bent by each of the sheets. An opening area of each of the through-holes of one of the sheets may be different from an opening area of each of the through-holes of another one of the sheets. The sheet may include at least one of a glass-wool, a wire net and a perforated plate.
It is preferable for effectively collecting the oil mist on the inner surface and securely holding the collected mist on the inner surface that the inner surface includes at least one of a glass-wool, a wire net, a spiral groove surrounding the discharge port as seen vertically, a groove extending vertically, and a shot-blasted surface.
It is preferable for restraining the oil mist from proceeding toward the discharge port and returning to the inner surface the oil mist released from the inner surface after being collected by the inner surface that the chamber containing therein at least one ring-shaped member having a tapered surface, and a diameter of the tapered surface decreases vertically downward.
It is preferable for restraining the oil mist from being introduced into the discharge port or passage when the inlet passage includes at an end thereof an inlet port opening to the chamber that the discharge port is arranged at a position lower than the inlet port. It is preferable for restraining the oil mist from being introduced into the discharge port or passage in a case of that the inlet passage extends horizontally to direct the flow axis of the mixture gas horizontally when the mixture gas reaches the chamber and includes at an end thereof an inlet port opening to the chamber, that the discharge port opens at a position lower than the inlet port.
It is preferable for restraining the mist of lubrication oil separated from the mixture oil at the inner surface from being introduced into the discharge port or passage that the baffle extends to a vertical position upper than the discharge port, and/or that the inlet passage extends horizontally to direct the flow axis of the mixture gas horizontally when the mixture gas reaches the chamber and includes at the end thereof an inlet port opening to the chamber, and the baffle extends to a position upper than at least a portion of the inlet port.